Automatic fire sprinkler head

ABSTRACT

Disclosed is a temperature controlled valve assembly for use in automatic fire extinguishing systems. The valve automatically and repeatably opens in response to heat generated by a fire and closes in response to a temperature decrease following extinguishment thereof.

United States Patent 1191 Johnson Apr. 9, 1974 [54] AUTOMATIC FIRE SPRINKLER HEAD 895,371 8/1908 Hopping 236/100 1,718,016 6/1929 Wh't t al.... 236/102 [75] invent: Oxford Mass- 1,850,371 3 1932 1366 132 236/99 3 Assigneez us Fire Control Corp. Oxford 1,884,794 10/1932 McKee 236/99 Masa 2,045,332 6/1936 Otto 236/99 X 2,774,539 12/1956 Eskin 236/99 X [22] Filed; May 14, 1971 2,830,767 4/1958 Herbenar 236/99 3,181,793 4/1965 MacCracken 236/237 [21] Appl. No.: 143,394

Primary ExaminerWilliam E. Wayner [52] US. Cl 169/19, 169/37, 236/99, Attorney, Agent, or Firm]0hn E, Toupa] 236/100, 251/302 [51] Int. Cl. A62c 37/06 [58] Field ofSearch..' 236/99, 100, 101, 102; 1 71 ABSTRACT 169/42 5 301 Disclosed is a temperature controlled valve assembly for use in automatic fire extinguishing systems. The [56] References C'ted valve automatically and repeatably opens in response UNITED STATES PATENTS to heat generated by a fire and closes in response to a 3,711,060 1/1973 Weinstein 251/11 temperature. decreasev following extinguishment 1,798,952 3/1931 Pellegrino 251/302 X thereof. 2,230,179 l/l94-l Cid 373,324 11/1887 Wheeler 236/100 14 Claims, 9 Drawing Figures PATENIEDAPR 9:914 I 3.802.510

Sum 2 or 3 WW Z/JZ/msm AUTOMATIC FIRE SPRINKLER HEAD BACKGROUND OF THE INVENTION This invention relates generally to valves and, more particularly, to automatically opening and closing temperature responsive valves for use in fire extinguishing systems.

Automatic fire extinguishing systems are useful for quickly extinguishing or controlling fires. The general acceptance of such systems is evidenced by their extensive use in commercial buildings such as factories, office buildings, apartment houses, stores, etc. In addition, their use has expanded recently for the protection of homes in residential areas. Conventional systems usually include a plurality of individual valve and nozzle combinations, with each valve independently controlled by a thermally fusible element. With independently controlled valves only those nozzles subject to heat produced by a fire are activated, rather than the entire system. Therefore, water damage does not occur in areas remote from the fire. Conventional fire valves, however, being of the one-shot type do not automatically close and reset so that water continues to flow after afire is extinguished unless the water supply to the building is manually shut off. For this reason, water is wasted,and unnecessary water damage in the area of the tire results. A typical example would be a grease fire confined to a single pan and quickly extinguished by-merely placing a cover over the pan. If however, a one-shot fire valve in the kitched had been activated by the heat generated before extinguishment, water would continue to flow needlessly until the water supply was turned off at the source. I

Valves that automatically close and reset upon cooling have been proposed to alleviate the probelms discussed above. Such valves typically employ a temperature sensing element such as gas filled bellows or a bimetallic strip. In order to provide the necessary magnitude of movement and force to operate the valve, the sensing elements in these devices are considerably larger than the corresponding fusible elements. The valves are therefore cumbersome and unsightly. The one-shot" valve possesses a further advantage with respect to conventional resettable valves. When the critical ambient temperature is reaches, a one-shot valve fully opens immediately, but previously known resettable valves open gradually as temperature increases or, in some cases, fail to respond at all as, for example, when gas has leaked from an expanding gas controller. Therefore, a full flow of water is not always or immediately provided by conventional resettable valves. For these and other reasons resettable valves are not widely used.

The object of this invention, therefore, isto provide a resettable temperature controlled valve that is small and compact, and responds rapidly and completely at a given predetermined temperature level.

SUMMARY OF THE INVENTION This invention is characterized by a valve with a valve member coupled to a temperature responsive control mechanism that is activated in response to an ambient temperature variation spanning a predetermined temmaterial is characterized by a sharply defined melting point and a substantial increase in volume during the solid to liquid transition. .The change in volume is used to mechanically control the valve members which. is

small in size and quickly and fully opens when the am-.

bient temperature reaches the melting point. Subsequently, as the ambient temperature declines, a substantial volume decrease occurs in the expansible material during a liquid to solid transition. The valve is then closed by a bias spring that opposes the expansion induced opening. Thus, the flow of water is automatically stopped after the fire is extinguished, and the valve can be recycled at any time.

According to another feature of the invention a cam lever mechanism is employed to amplify the valve closure force applied by the bias spring. The lever mechanism insures full closure of the valve and reduces the bias requirements of-the spring which can therefore be of minimal size. Also, a spring is utilized that exerts an increasing bias as the valve moves from open to closed position. Thus, maximum closure force is available for the final compression of the crystalline material at the end of a valve closing cycle.

Another feature of the invention is the utilization of a reciprocating coupling between the valve member and the temperature responsive control mechanism that moves in a direction transverse to the flow of water in the valve. This configuration results in a small compact valve which is more pleasing in appearance than previous resettable models. In addition a valve with this configuration can be substituted directly for oneshot valves in existing systems. I

Still another feature of the invention is the disposition of the body of expansible material out of the path of flow of the fluid and the utilization of a deflector to shield the body from the discharge of fluid. This insures an accurate sensing of ambient temperature by preventing splashing fluid from affecting the temperature of the sensor.

Yet another feature is thermal insulation between the housing of the valve and the body of expansible material. When the valve is open the temperature of the housing may be affected by the flow of fluid therethrough but thermal insulation prevents the temperature change from affecting-the body of expansible material thereby insuring an accurate sensing of ambient temperature.

Another embodiment of the invention includes a sec-- ond temperature responsive actuator that allows the valve to open but prevents its'closure with ambient temperature above a certain level. The second actuator responds to a lower temperature than the primary actuator and therefore provides a temperature delay for reclosure that insures full extinguishment of the fire.

DESCRIPTION OF THE DRAWINGS These and other features and objects of the invention will become more apparent upon a perusal of the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 shows a sectional view of one preferred embodiment of the invention utilizing a linear configuration;

FIG. 2 shows a sectional view of another preferred embodiment of the invention utilizing mechanical amplification to increase the force exerted by the bias spring; l

FIG. 3 shows a sectional plan view of the embodiment shown in FIG. 2 taken along the lines 3--3;

FIG. 4 shows still another preferred embodiment of the invention utilizing a reciprocating slide valve;

FIG. 5 is a sectional plan view of the embodiment shown in FIG. 4 taken along lines 55;

FIG. 6 shows a sectional elevation view of yet another preferred embodiment utilizing a ball valve;

FIGS. 7 and 8 show another preferred embodiment with the valve in open and closed positions, respectively; and

FIG. 9 is a sectional view of the embodiment shown in FIG. 8 and taken along lines 9-9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 there is shown a sectional view of a embodiment 21 of the invention including a housing 22 that defines an inlet opening 23 and a plurality of outlet openings 24. Enclosed in a cavity 25 within the housing 22 is a valve member 26 that is connected by a reciprocating actuator 27 to a temperature responsive control mechanism 28. Contained within the control mechanism 28 is a body of expansible material that exhibits a substantial volume change during the liquid to solid transition. The melting point can be selected accurately from a wide temperature range by varying the composition of the material. Suitable mechanisms of this type are disclosed, for example, in U.S. Pat. Nos. 2,815,174; 2,938,384; and 3,092,322. Changes in volume of the material within housing 28 produce reciprocating mechanical motion of the operatively coupled actuator 27. Also disposed within the cavity 25, and positioned between the top thereof and the valve member 26 is a bias spring 29 that presses the valve member toward the bottom of the cavity, thereby covering and closing the outlets 24. Projecting from the annular surface of the valve member 26 are a plurality of guides 31 that keep the valve member transversely centered within the cavity 25. When the valve member 26 is forced upward by the actuator 27, thereby opening the outlets 24, water freely flows from the inlet 23 to the outlets 24 through-a plurality of gaps 32 disposed between and defined by the guides 31. Disposed below the outlets 24 and in the path of discharge is a deflector 33 to disperse the flow of water. Between the deflector 33 and the actuator 28 is a large body 34 of thermal insulation material that prevents the flow of water around the deflector 33 from influencing the temperature sensed by the control mechanism 28. An upper portion 35 of the housing 22 is threaded so that the embodiment 21 may be installed in existing fire extinguishing systems by simply changing valves.

During operation of embodiment 21 valve member 26 is normally in the closed position as shown in FIG. 1, and held in place by bias spring 29. In the event of a fire, heat raises the ambient temperature and the tem-' perature of the control mechanism 28 quickly reaches the melting point of the expansible material. The melting point is sharply defined, and therefore the entire body of expansible material quickly melts and the resultant increase in volume forces the piston actuator 27 in an upward direction. The force of the spring 29 is overcome and the valve member 26 is moved to the open position, uncovering the outlets 24. Water then flows through the inlet 23, the gaps 32 and the outlets 24 over the deflector 33 thereby spraying the surrounding area. When the fire is extinguished, as evidenced by a decrease in ambient temperature, the temperature of the control mechanism falls to below the melting point of the expansible material, and the body of expansible material then solidifies and contracts. As the contraction takes place the spring 29 pushes the valve member 26 back to the closed position thereby stopping the flow of water automatically. Typically, the actuator mechanism 28 would be selected to have a response in a temperature range between l40-500F.

Referring now to FIGS. 2 and 3 there is shown another embodiment 37 of the invention including a housing 38 defining an inlet opening 39 and an outlet opening 41. Within the housing 38 is a cavity 42 with an eccentric cam 43 resting on a lower surface 44 thereof. The eccentric cam 43 defines a valve opening 45 and is pivotally mounted by a pin 46. A bias spring 47 holds the cam 43 in a closed position, that is, with the valve opening 45 horizontally displaced from the outlet 41. Mounted on the housing 38 is a temperature responsive control mechanism 48 that is operatively coupled to the cam 43 by a reciprocating actuator 49. The control mechanism 48 is similar to that denoted by number 28 in embodiment 21. The cam 43 mechanically couples the spring 47 to the actuator 49 as a lever, thereby amplifying the force exerted by the spring 47 on the actuator 49. Disposed below the control mechanism 48 is a deflector 51 to prevent the cooling of the control mechanism by splashing water discharged against a dispensing deflector 50 located below the outlet 41. An upper portion 52 of housing 38 is threaded so that the unit 37 may be easily substituted for conventional fusible type nozzles in existing fire extinguishing systems.

During operation of embodiment 37 the bias spring 47 normally holds the eccentric cam 43 in the closed position. Heat, caused by a fire, raises the ambient temperature and therefore the temperature of the control mechanism 48 until the melting point of the expansible material is reached; The body of the expansible material then melts quickly, and the associated increase of volume forces the actuator 49 to the left as viewed in FIG. 3. The eccentric cam 43 is thereby'rotated clockwise to the open positions, that is, with the valve opening 45 disposed between the inlet 39 and the outlet 41. Water then flows through the valve 37. When the tire is extinguished and the ambient temperature drops, the body of expansible material solidifies, with an associated decrease in volume. As the decrease in volumes occurs, the bias spring 47, through the lever action of the cam 43, forces the actuator 49 to the right as viewed in FIG. 3. The valve 37 is then closed,.and ready to be recycled. The mechanical leverage furnished by the cam 43 amplifies the force provided by the spring 47 to insure full retraction of the actuator 49 and thereby full closure of the valvevThis is an important feature in that actuator mechanisms of this type offer a substantial resistance to full retraction because of the elastic nature of internal gaskets (not shown) that are generally employed. Thus, the lever motion of cam 43 permits use of the full stroke of the actuator 49 while minimizing the bias requirements of the spring 47. Another important feature of embodiment 37 is that the reciprocating movement of the actuator 49 is transverse to the direction of fluid discharge from the outlet 41. Because of this relationship and the use of a slide valve, the control mechanism can be mounted out of the path of fluid flow to provide an extremely compact unit.

Referring now to FIGS. 4 and 5 there is shown yet another embodiment 55 of the invention including a housing 56 that defines an inlet opening 57 and an outlet opening 58. In a cavity 59 in the housing 56 is a reciprocating slide valve member 61, disposed between a reciprocating actuator 62 and a bias spring 63. The bias spring 63 normally holds the valve member 61 in a closed position, that is with a valve opening 64 horizontally displaced from the inlet opening 57 and the outlet opening 58. A temperature responsive control mechanism 65 is operatively coupled to theactuator 62. The temperature sensitive control mechanism 65 is similar to the temperature sensitive control mechanism denoted by numeral 28 in the embodiment 21. Disposed below the control mechanism 65 is a deflector 66 to prevent water from splashing on the control mechanism when discharged against the partially shown dispensing deflector 60. An upper portion 67 of the housing 56 is threaded so that the embodiment 55 also may be utilized in existing fire extinguishing systems.

During operation of the embodiment 55, heat from a tire raises the ambient temperature until the melting point of the body of expansible material is-reached. As the body of expansible material melts there is a substantial volume increase, forcing the actuator 62 and the valve member 61 to the left. The valve member 61 is therefore placed in the open position, that is with the valve opening 64 in line with the inlet opening 57 and the outlet'opening 58. Water then flows through the valve 55 and is dispersed on the surrounding area by the deflector 60. When the fire is extinguished, and the .ambient temperature cools to below the melting point,

the body of expansible material solidifies and contracts. During. contraction the bias spring 63 forces the valve member 61 to the right, that is into the closed position, thereby stopping the flow of water. The valve 55 may now be recycled. As in embodiment 37, the reciprocating movement of the actuator 62 is transverse to the direction of fluid discharge, thereby promoting a compact structure.

Referring next to FIG. 6, there is shown yet another embodiment 71 of the invention including a housing 72 that defines'an inlet, opening 73 and an outlet opening 74. Enclosed in a cavity 75 in the housing 72 is a ball valve member 76, with a valve opening 77 therethrough. Spanning the cavity 75 is a combination of a reciprocating actuator 78 aligned with a bias spring 79. The reciprocating actuator 78 is operatively coupled to a temperature sensitive control mechanism 80, that is similar to the temperature sensitive control'mechanism 28 in the embodiment 21. A lower portion 81 of the actuator 78 comprises teeth 82 that mesh with a gear 83 affixed to the ball valve member 76. Transverse reciprocating motion of the actuator 78 therefore causes the ball valve member 76 to rotate from a closed to an of a contained body of expansible material. As the body of expansible material melts there is a substantial in crease in volume, forcing the reciprocating actuator 78 to the left, thereby rotating the ball valve member 76 counterclockwise as viewed in FIG. 6. This rotation places the ball valve member 76 in an open position, that is with the valve opening 77 aligned with the inlet opening 73 and the outlet opening 74. Water then flows through the valve 71. After the fire is extinguished the ambient temperature lowers until the temperature of the control mechanism is below the melting point of the body of expansible material. Simultaneously with the resulting solidification and decrease in volume the bias spring 79 forces the actuator 78 to the right, thereby rotating the ball valve member 76 to the closed position. The flow of water is then stopped, and the valve 71 is reset and may be cycled again. Again, movement of the actuator 78 is transverse the direction of fluid discharge.

Referring now to FIGS. 7-9, there is shown another embodiment 91 again including a housing 92 with an inlet opening 93 and an outlet opening 94. Within the housing 92 is a cavity 95 retaining an eccentric cam 96 similar to the cam 43 shown in FIG. 3. The cam 96 defines a valve opening 97 and is pivotally mounted on a pin 98. A bias leaf spring 99, mounted on pins 101 and 102, urges the cam 96 toward closed position shown in FIG. 8, that is, with the valve opening 97 horizontally displaced from the outlet 94. An auxiliary helper spring 100, also mounted on pin 102, also engages the cam 96 and further biases the opening 97 toward closed position. Mounted on the housing 92 is a primary temperature responsive control mechanism of the type previously described and coupled to the cam 96 by a reciprocable actuator 104. Mounted below the housing 92 is a deflector 105 for dispersing fluid discharged through the outlet 94 while an upper portion 106 of the housing 92 is threaded to facilitate assembly into a fire extinguishing medium supply system.

open position. Disposed below the control mechanism The temperature responsive mechanism 103, the cam 96 and the bias springs 99 and function in the same manner as embodiment 37 to provide automatic control of extinguishing medium discharge in response to ambient temperature. However, even more selective control is made possible by a latching'cam 107 freely mounted for rotation in the cavity 95 on a pin 108. An auxiliary temperature responsive mechanism 109 is mounted on the housing 92 and has a reciprocable piston 111 that engages the cam 107. Again, themechanism 109 is preferably a wax filled element of the type described above. I

The mechanism 109 is selected for response to an ambient temperature below that required to actuate the mechanism 103. For example, the wax in mechanism 109 would melt at an ambient temperature of about F while the wax in mechanism 103 would melt at an ambient temperature of about F. Thus, in response to rising ambient temperature accompanying a fire, the wax in mechanism 109 will first melt forcing the piston 111 against the locking cam 107 which is restrained by engagement with the cam 96. Preferably, only the final portion of the pistons outward stroke is utilized so as to limit the internal pressure within the mechanism 109 that is restrained. A further rise in ambient temperature activates the mechanism 103 producing outward movement of the actuator 104 and urging the cam 96 toward the open position shown in FIG. 7. Fire extinguishing fluid discharge through the outlet 94 is thereby initiated. During opening movement of the cam 96 its surface 115 moves across the engaging apex 116 on auxiliary cam 107 which initially remains stationary. However, when the relative positions shown in FIG. 7 are reached, the auxiliary cam 107 is moved by the previously activated piston 111 forcing the apex 116 into a recess 117 formed in the surface 115. This engagement between the apex 116 and the recess 117 latches the cam 96 in the open position. Thus, a reduction in ambient temperature is below the l80F setting of the mechanism 103 will not result in closure of the valve unless a further drop to below the 140F setting of the mechanism 109 occurs. At that temperature, the wax in the mechanism 109 solidifies and contracts relieving the force exerted on the auxiliary cam 107 by the piston 111. This, in turn allows the bias springs 99 and 100 to pivot the cam 96 into closed position after first forcing the apex 116 out of the recess 117. The thermal delay provided by the latching cam 107 enhances the probability that a fire is fully extinguished before valve closing is effected. Thus, the possibility of rekindling that might produce cycling of the valve between open and closed positions is reduced. Another desirable feature of the embodiment 91 is the leaf spring 99 which is engaged at a position nearer to its heel 119 with the cam 96 in a closed position (FIG. 8) than in an open position (FIG. 9). For this reason, the spring 99 exerts a variable force on the cam 96 that is greater in the closed position than in the open position. This is desirable because, as described above, the force required to fully move the piston into the mechanism 103 is greatest during the final portion of the inward stroke. The helper spring 100 compensates for this action of the spring 99 by exerting maximum force with the cam 96 in the open position shown in FIG. 7 thereby insuring initial closure movement.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For example, features shown in the individual embodiments can be interchanged as desired; e.g., thermal insulation of the type 34 shown in embodiment 21 can be used in any of the embodiments shown in FIGS. 2-9. It is to be understood, therefore, that the invention can be practiced otherwise than as specifically described.

What is claimed is: l. A valve assembly for use in automatic fire extinguishing systems and comprising: v a. a housing defining inlet and outlet openings;

b. a rotary slide valve member movable between closed and open positions, said valve member preventing fluid flow through said inlet and outlet openings when in said closed position and permitting the discharge of fluid available at said inlet opening through said outlet opening when in said open position;

0. actuator means comprising a resprocative member for moving said valve member between said open and closed positions, said reciprocating member being movable in a direction transverse the direction of fluid flow through said valve member and engageable therewith so as to exert a rotary force on said valve member; I

d. temperature responsive control means operatively coupled to said actuator means and adapted to automatically poroduce movement of said valve member to said open position in response to ambient temperatures above a given level and movement of said valve member to said closed position in response to ambient temperatures below said given level, said control means comprising a body of expansible material of a type that experiences substantial volume increase during changes between solid and liquid states and substantial volume decreases during changes between liquid and solid states, both said changes of state being induced by changes in temperature and occurring at said given level; and

e. fluid dispersing means supported by said housing means in close proximity to said valve member and disposed to directly receive fluid discharged through said outlet opening and to produce a predetermined distribution pattern with the discharged fluid.

2. A valve assembly according to claim 1 wherein said temperature responsive control means comprises biasing means opposing movement of said valve member to said open position.

3. A valve assembly according to claim 2 wherein said control means further comprises amplification means for substantially amplifying the force applied to said actuator means by said biasing means.

4. A valve assembly according to claim 3 wherein said amplification means comprises a lever mechanism.

5. A valve assembly according to claim 4 wherein said lever mechanism comprises an eccentric cam coupled between said reciprocating member and said biasing means.

6. A valve assembly according to claim 1 wherein said temperature responsive control means comprises biasing means opposing movement of said valve member to said open position.

7. A valve assembly according to claim 6 wherein said control means further comprises amplification means for substantially amplifying the force applied to said actuator means by said biasing means.

8. A valve assembly according to claim 3 wherein said amplification means comprises a lever mechanism.

9. A valve assembly according to claim 8 wherein said lever mechanism comprises an eccentric cam coupled between said reciprocating member and said biasing means.

10. A valve assembly according to claim 1 wherein' said body of expansible material is disposed out of the path of fluid discharged through said outlet opening.

11. A valve assembly according to claim 10 including deflector means for shielding said body of expansible material from fluid discharged through said outlet opening.

12. A valve assembly according to claim 10 wherein said body of expansible material is disposed above said fluid discharge path from said outlet opening.

13. A valve assembly according to claim 1 wherein said given temperature level is in a range between and 500F.

14. A valve assembly according to claim 1 wherein said housing means defines an externally threaded coupling portion that defines said inlet opening in close proximity to said movable valve member. 

1. A valve assembly for use in automatic fire extinguishing systems and comprising: a. a housing defining inlet and outlet openings; b. a rotary slide valve member movable between closed and open positions, said valve member preventing fluid flow through said inlet and outlet openings when in said closed position and permitting the discharge of fluid available at said inlet opening through said outlet opening when in said open position; c. actuator means comprising a resprocative member for moving said valve member between said open and closed positions, said reciprocating member being movable in a direction transverse the direction of fluid flow through said valve member and engageable therewith so as to exert a rotary force on said valve member; d. temperature responsive control means operatively coupled to said actuator means and adapted to automatically poroduce movement of said valve member to said open position in response to ambient temperatures above a given level and movement of said valve member to said closed position in response to ambient temperatures below said given level, said control means comprising a body of expansible material of a type that experiences substantial volume increase during changes between solid and liquid states and substantial volume decreases during changes between liquid and solid states, both said changes of state being induced by changes in temperature and occurring at said given level; and e. fluid dispersing means supported by said housing means in close proximity to said valve member and disposed to directly receive fluid discharged through said outlet opening and to produce a predetermined distribution pattern with the discharged fluid.
 2. A valve assembly according to claim 1 wherein said temperature responsive control means comprises biasing means opposing movement of said valve member to said open position.
 3. A valve assembly according to claim 2 wherein said control means further comprises amplification means for substantially amplifying the force applied to said actuator means by said biasing means.
 4. A valve assembly according to claim 3 wherein said amplification means comprises a lever mechanism.
 5. A valve assembly according to claim 4 wherein said lever mechanism comprises an eccentric cam coupled between said reciprocating member and said biasing means.
 6. A valve assembly according to claim 1 wherein said temperature responsive control means comprises biasing means opposing movement of said valve member to said open position.
 7. A valve assembly according to claim 6 wherein said control means further comprises amplification means for substantially amplifying the force applied to said actuator means by said biasing means.
 8. A valve assembly according to claim 3 wherein said amplification means comprises a lever mechanism.
 9. A valve assembly according to claim 8 wherein said lever mechanism comprises an eccentric cam coupled between said reciprocating member and said biasing means.
 10. A valve assembly according to claim 1 wherein said body of expansible material is disposed out of the path of fluid discharged through said outlet opening.
 11. A valve assembly according to claim 10 including deflector means for shielding said body of expansible material from fluid discharged through said outlet opening.
 12. A valve assembly according to claim 10 wherein said body of expansible material is disposed above said the fluid discharge path from said outlet opening.
 13. A valve assembly according to claim 1 wherein said given temperature level is in a range between 140* and 500*F.
 14. A valve assembly according to claim 1 wherein said housing means defines an externally threaded coupling portion that defInes said inlet opening in close proximity to said movable valve member. 